Hi, before I have a look if I could help to contribute support for the license attribute: is there a known reason why pkg_deb does not already support the license attribute? Can this already be set another way (that I am not seeing)?

Expected e.g.,

pkg_deb(
  ...
  license = "BSD-3-Clause",
  ...
)

$ dpkg -I foo.deb
...
 License: BSD-3-Clause
...